"I'm too old for yoga!"
I always tell my students, "Start moving before you can't move anymore. You don't want to be a burden to your children or other people as you age".
The practice of yoga teaches us to take care of ourselves before others.
By keeping yourself active, you are able to lead a more fulfilling life!
Yoga posture (asana) practice would be slightly more challenging in the beginning especially if you have more years of habits to break away from, but it is still better to start NOW than never.
Start moving, live a fulfilling life!
That, to me is the practice of yoga. It is a practice to learn about yourself, your body and you!